wenty-two soldiers from the United Arab Emirates were killed in Yemen while taking part in a Saudi-led campaign against the Houthis, UAE state news agency WAM said on Friday.

The Houthis said they fired a rocket at a weapons cache in a camp used by Gulf coalition forces in the central Marib area, killing dozens of Emirati and Yemeni soldiers and destroying a number of Apache helicopters and armed vehicles.

Residents in Marib told Reuters they saw fire raging at the camp and plumes of smoke.

WAM did not give details on how the soldiers died.

Saudi Arabia and a coalition of other Sunni Muslim Gulf states have been fighting since March to restore Yemen’s exiled government and repel the Iran-allied Shi’ite Houthis, who took control of the capital Sanaa in September last year.

Before the latest incident, at least five Emirati soldiers had been killed in Yemen since the offensive began.

Militias and army units loyal to President Abd-Rabbu Mansour Hadi, who is taking refuge in Saudi Arabia, have made advances toward the Houthi-controlled capital in the last two months but the group remains ensconced in Yemen’s north and military and civilian casualties mount in nationwide combat every day.

The coalition has been supporting anti-Houthi fighters with air strikes, military training and the delivery of tanks and heavy artillery.